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. i n 2 g Maweh Y G. A. KRAMER PROCESS oF PRODIKJCING LUBRICATXNG oILs Filed May 9, 1925 Patented Mar. l, i927. i

GUSTAV A. KRAMER, OF CONCORD, CALFORNIA, ASS-EGNOR, BYIIIESNE ASSIGNMENTS,

T SIMPLEX REFINING COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORA- TION OF CALIFORNIA. y'

PROCESS OF PRODUCING LUBRICATING OILS.

My invention relates to the art of producing lubricating oils from petroleum. The term petroleum as used herein includes not only crude petroleum but also various petroleum derivatives produced by distiilation or otherwise.

It is an object otl lnyinvention to provide a process by which petroleum may be re- [ined to produce lubricating oils which are heavier than those produced by means ot ordinary vacuum distillation.

It is a further object of my invention to provide a process by which I can produce petroleum lubricating oils which are Vvtree from undesirable products Which would tend to lower the initial commercial valueL oi the oil or cause a slouT deterioration thereof subsequent to its production.

It is a further object of my invention to provide a process by which it is possibleto use steam for theproduction of lubricating oils at very loW absolute pressures, and in which, even at these low absolute pressures. the condensation of the steam and other ing water ot readily available tcnnperature. rlhe term cooling Water of readily available temperaturclas used herein is intended to designate cooling` water produced by cooling towers or spray ponds in the temperate lZone. lit is a turther object otmy invention to providev aprocess 'for the production oit lubri :ating oils troni petroleum in which the distillation is accomplished by the use of steam, but in which the consumption of steam is kept below that obtained in any previously known steam distillation process rlhe annexed drawing represents diagraminatically an apparatus by which the invention may be carried on, the individual. pieces of apparatus being old in the art and being represented partly in section to better illustrate theirk internal structure. This apparatus may conveniently consist oit the following mainmernbers: A tubular preheater l, a still 2, a lubricating oil condenser 3, a vapoircooler 4t, an ejector 5, a cracked products condenser 6, a lubricating oil cooler 7. a separator t, and a steam condenser' 9. The greater portion et this ap- ]'Jaratus is designedto operate under vacuum and is so constructed to resist external` pressure..

vapors may be accomplished bynsing coolV Application filed May 9, 1925. Serial No. 29,047.

rEhe preheater l consists of any'convenient form of preheating device, that shown consisting of a coil ot pipe l0 carried in furnace ll heated by any convenient means, not shown. The oil to be preheated is fed into the coil l0 through a pump l2 and the heated oil is fed through a pipe 13 into the still 2. A valve 11i may be placed in the pipe 13 for holding the oil in the coil l0 under some slight pressure to prevent the formation ot vapors and foaming in the preheater'and also for shutting off the prelieater l from the still 2. v

The still 2 may be ot any convenient Jform,

that shown consisting of a tubular body l5 f having a dome 16- A preitorated lsteam pipe 17 is placed in the bottom of the stillf 2, through which steam may befblovvn through the charge ot' oil therein, the steam 'pipe 17 being provided, with a valve 18. The still12 may be set in a 'furnace 19 which is heated by means otl a burner 20 controlied by a valve 2l. Heat insulation 22 surrounds the tubular still 2 and the dome 16." Oil vapors'and steam are carried from the dome lo' through a pipe 23 into the lubricating oil condenser 2L The lubricating oil condenser chosen to .illustrate the invention comprises a tubular shell 24, having heads 25 at either end thereof. Tubes 26 are provided between the heads 25, air heilig blown through these tubes through a pipe 27 from a blower 28. damper or air valve 29 is provided in the pipe 27 for regulating the flow ot air therethrough. The lubricating oil condenser 3 is also provided With an insulating ljacket 3() to prevent heat losses therefrom.

Any lubricating oil condensed in the condenser 3 is passed through a. siphon or loop 31 into the lubricating oil cooler 7, which comprises a tank 32 through which Water may be circulated by means of pipes 33 and 34. The cooler also comprises a Worm 35 set in the Water of the tank 32, this Worm eX- tending through the bottom of the tank 32 and connecting With a pipe 36 having a valve 37. The pipe 36 is connected to alubricating oil pump 38.

Any uncondensed gases or vapors passing through the lubricating oil condenser 3 are delivered through a pipe 39 to the vapor cooler 4. This comprises a tanker@ through which Water clay he circulated by means i" pipes 41 and 42. In the tank 4() is a worm 43 which connects through a pipe 44 with the ejector 5.

rEhe ejector is of any well known forni, lbeing 'ted with steam trom ay pipe V45 through a valve 46. The ejector actsV to withdraw gas and vapor 'from the pipe 44 and i'orce it at al higher pressure through a pipe 47 into the cracked products condenser 6. y

The cracked products condenser. 6 comprises awtank 46 through which water may U'be circulated by means vot pipes 49 and have been removed.

50. Situated in the tank 46 is a worin 5l intov which the vapors and uncoiidensed gases from the ejector 5 are ted, the worin 51 connecting through a pipe 52 with the top of the separator 6. i

Any liquid condensed in the condenser 6 is separated in the separator 8 and delivered through 4a valve 53 to al cracked products pump 54.

Uncondensed gases or vapors pass through a pipe 55 into the steam condenser 9, which may consist oft' a tubular inen'iber 56 having a water spray 57v fed through a pipe 56 having avalve 59. yTater is sprayed downwardly through the interior ot the member ,56, and this water and any condensates formed -therein are delivered through a pipe 60 having a valve 61 to the water pump 62. Air and other uncondensable gases collecting inside the member 56 are withdrawn through' a pipe 63 having a valve 64 by a gas pump 65.

For convenience I provide a vacuum gage.' 66 on the still 2V and a similar vacuum gage 67 on the steam condenser 9. A thermometer 68 is provided tor measuring oil temperature in the sill ,2, and thermometers 69 and 70 are provided on the inlet and outlet sides of the lubricating oil condenser 3. Other gages and indicating or recording devices may be supplied it desired.

The method ot' operation ot my invention is as follows: Y

I prefer to use as a charging stock petroleum Jfrom which the more volatile 'fractions I have round that in the practical operation of the invention an oil trom which all fractions boiling below 600C F. at atmospheric pressui'cliave been distilled is quite suitable for my purpose. The charging stock is fed through the preheater 1 and is delivered into the still 2, preferably at a temperature near that at which it is desired to start the distillation. The valve 14 is closed as soon as the still 2 is charged. The valves 46, 37, 53, 59 and 18 being closed, the absolute pressure within the apparatus may bev brought down to the desired point by operating the air pump which pumps off the air andI vapors to any desired degree. Heat maybe applied to the charging stock in the still 2 by means of the burner 20 and its temperature readily determined by the therniometer V66.

In practice I may elect, for example, vto operate the still 2 atan absolute pressure ol: 5 millimeters oi mercury, as indicated by the gage 66, and the pump 65 is utilized to'` produce this high vacuum or low absolute pressure initially. Steam is admitted whenever desired through the pipe 17 by opening Y the valve 18 so that a mixture oi5 oil vapors and steam leaves the still 2 throughthe pipe 23. In practice I' may suppl-y, tor example, siiliicient steam so that the vapor passing through the pipe 23 contains 10 per cent ot mercury. Atthis extremely ,low partialV vapor pressure the oil vaporizes readily and there will be distilled from the petroleum a very superior grade of lubricating oil itt the petroleum is heated to temperatures above 3000 F. l y

l have found that however carefully petroleum may be initially relined to produce the charging stock which `l intend to` use,

yand however carefully they apparatus described herein inay be operated, there will inevitably appear in the still 2 certain cracked products. These products are formed by the breaking up of the hydrocarbon molecules of the petroleum into crackedl molecules having a smaller Vnumber o carbon atoms. rlfhese cracked molecules are unsaturated and have a lower boiling point tha the petroleum molecules Jtrom which they are Ytermed. Having a lower boiling point they pass very readily as a vapor through the pipe 28, and being unstable they tend toA give any lubricating oil in Whicli they are allowed to condense certain very undesirable qualities, such as a bad color and odor, and a tendency to produce resin-likesubstances. I have found that by the use of steam in the still 2, the amount oi these cracked products produced can be minimized duc to the low partial vapor pressure and the consequent low tei'npcrature at which distillation occurs.

l lind, however, that it is impossible to prevent the 'formation ot a small percentage ot these undesirable coniiliiounds even.V it amounts oit steam tar in excess olf those above specified are used. Some of these uiidesirable cracked product may otcourse polymerize in the still 2, or later, to form other compounds.

lt a particular object of my invention to provide means for preventing undesirable compounds from appearing in the lubricating oil. This can be accouiplished, for elo llt) -ainple, by the use of the condenser 3 proviees a very eliicient method ot temperawhich ture regulation. By blowing air frein the pump 28 through the tubes 26, l am able to cool the oil` vapors surrounding these tubes to any desired degree, and by a manipulation ot' the valve Q9 l can readily change the degree ot coolingproduced inthe `condenser S I lind that it' the temperature-erop ofl the vaporsin passing through the condenser l `is kept very small, it is possible to practically eliminate any condensation ot undesirable products.

In practice l may operate my apparatus with a drop in ten'iperature in the condenser 3 ot trom l0@ F. to 50 lso that the vapors leaving the oil condenser 8 through the pipe 239 are at a temperature as indicated by the `thermometer i ot only trom 1GO to5dO F.

below the temperature ol the vapors entering this condenser through the pipe Q3 as indicated bythe therniom'eterb. By so open ating l am able to deliver to the Siphon 3' a` lubricating oil which is substantially tree trom undesirable products. rlhe siplion 3l is kept filled with this oil and acts as a seal to prevent any vapors trom passing into the cooler 7 and being condensed therein. The lubricating oil which is delivered to the cooler 7 at a temperature slightly below y that maintained in the still 2 is cooled and is delivered at a lower temperature through the pipe 36 and valve 37, being withdrawn through the pump 38 and delivered to suitable storage, not shown.

rhe vapors passing through the pipe 39 are then very materially cooled in the cooler el. This cooler is supplied with cooling water and may produce a drop in temperay ture. ot several hundred degrees. rlhe principal object of the cooler l is to reduce the volume ot the steam and other vapors and thus reduce the steam consumption in the ejector 5.

rlhe ejector is ay convenient device 'lor moving large volumes ot vapor a fa, low increase .inpressure Steam is admitted thereto trom the pipe by opening the valve slt). ln practice it may be falled upon to raise the pressure on the vapors from 5 milli meters ot mercury to approximately 5U millimeters ot' mercury. The steam and other Vvapors are then passed at this higher pressure into the condenser G, in which the undesirable products tend to condense out. Some ot these undesirable products may, in tact, start to condense in the condenser 'l and are then delivered by the ejector into the condenser 6.

The fluids leaving the condenser Gathi'ough the pipe 52 are preferably at such a temperature that no substantial condensation ot steam has occurred, but that substantially all ot the undesirable or cracked products have been condensed so that they can be separated inthe separator` 8 and withdrawn through the valve 58 by means ot the pump 5st. These undesirable products consist largely ot'craelzed, unsaturated, and unstable hydrocarbons which, however, have certain uses and some commercial value. vrlhey are delivered tromthe pump to suitable storage,

' not shown.

ot the pump 62. rlhe air and uncondensed gases are withdrawn through the pipe 63 and the valve (il by the pump 65.

My invention ditlers from previous attei '1pts to producelubricating oil by means ot steam distillation under vacuum in that l am able to obtain an absolute pressure n; the still Q'which is tar belowthe vapor pressure o'l' the available cooling` water since' steam would have to be cooled `below 320 F. to condense at an absolute pressure ot t6 millimeters ot mercury. lt, therefore. I

y atten'ipted to use pressures ot 5 millimeters ot mercury or below in the still l and attempted to condense the steam such pressures, it would be necessary for me to provide retrigerating means for this iondensation. Y

By utilizing the ejector 5 I am able to increase the absolute pressure ot the steam before its condensation to a point at which the steam can be readily condensed by ordinary condensing equipment, such as is used in steam power plants, and by the use ol cooling1 water at a temperature which can ordinarily be easily obtained in tenu'ierale climates thrmighout the year by well known means.

My invention also dilters ilronrprevious vacuum processes using steam. lA maintain the absolute total pressure in the still antiiciently low to obtain low partial oil vapor pressures without the .injection ot large quantities ol steam. This is quite ucc irlv it an economical process is lo result, as steam is quite expensiveI and by keeping the consumption of steam down to lO per cent by weight of the lulfnicating oil produced l am able to refine lubriat'iN oils cheaply and etlieiently.

The steam also plays au important part in preventing the comlensation ot the undesirable products with the lubricating oil. rl`hese undesirable products are present in the vapors passing through the pipe 23 in comparatively small quantities. it being possible to maintain this percentage well below l per cent ot the total lubricating oil produced. The partial vapor pressure of these on the undesirable fractions would still be low at the point where they entered the oil condenser 3, but inasmuch as substantially all ot the lubricating oil vapors are condensed in the oil condenser 3 the partial vapor pressure on the undesirable vapors in the oil condenser 3 wouldbe substantie. ly the total. pressure. rthis great increase in vapor pressure oit tne undesirable compounds would cause them to condense more readily and considerable quantities would appear in the lubricating oil..

By mixing with the oil vapors a large volume ol steam-which is not condensed in theV condenser 3, l am able to maintain an extremely low partial vapor pressure on the undesirable vapors which do not condense, and which are tliereiore readily carried ovei' with the steam. The steam acts also as a diluting agent for the undesirable compounds Vto prevent their absorption in the lubricating oil.

I claim as my invention:

l. A method of distilling petroleum Vto produce lubricating oils which comprises: prodicing a mixture which contains lubrieating oil vapors, steam and iixed gases at a primary' pressure belovi7 vatn'iosplieric rpressure,ithis pressure being so low that steam :annot be condensed `thereunder at available cooling water temperatures; cooling said mixture to a temperature at which substantially all the lubricating oil vapors will condense witliout substantial condensation of said steam; scgregating the lubricating oil so condensed; increasing the pressure on the remaining constituents of said mixture to a pressure substantially below atmospheric pressure but at which steam readily condenses at available cooling water temperatures; cooling said other constituents to a ten'iperature at which said steam is readily condensed; segregating the water so produced; and segregating and removing any 'apors or gases remaining atte'r the condensation oiE said steam.

A method of distilling petroleum to p roduce lubricating oils which comprises: pro ducing a charging stock by distilling lrom a raw material all constituents which are more 'volatile than the lubricating oil which it Ycannot becondensed thereunder atV available cooling Water temperatures; cooling said mixture to a temperature at which substan' tially all the lubricating oil vapors will con densel without substantial condensation of said steam; segregatmg the lubricating oil so vapors or gases remaining after Athe condensation oit said steam.

3. A method of distilling petroleum to pro duce lubricating oils which comprises: pro ducing a mixture ol lubricating oil vapors, undesirable vapors, steam and lixed'gases;

condensing the lubricating' oil vapors at av pressure so lowthat fsteam cannotrbe con densed therefrom at available cooling water temperatures, suicient steam being supplied to prevent the siiiiultaneous condensation ot' said undesirable vapors; and subsequently increasing the pressure on said undesirable vapors, steam and .fixed gases to a point at which said steam is readily condensed, at

available cooling water temperatures.

Ll. A method' or distilling petroleum to.

produce lubricating oilsI which comprises:

producing a mixture o't' lubricating oils' vapors, undesirable vapors, steamand `lixed gases; condensing the lubricating oil vapors at a pressure so low that stean'rcannot be condensed therefrom at available cooling water temperatures, sufficient steam being supplied to prevent the simultaneous condensation ot said undesirable vapors; cooling the undesirable vapors, steam and fixed gases to reduce their volume; and subsequently increasing the pressure on Vsaid undesirable vapors, steam and l'ixed gases to a point at which said steam is readily condensed at available cooling water temperatures.

5. A method of producing lubricating oils from petroleum which comprises: distilling a charging stoel; in the presence o'f steam at an absolute pressure lower than the vapor pressure ot the available cooling water; condensing the oil vapors at substantially this saine pressure; and compressing the steam to a pressure atwhich it can be condensed by l said cooling water.

6. A. method oi producing lubricating oils from petroleum which comprises: distilling a charging stock in the presence ot steam at an absolute pressure lower than the vapor pressure of the available cooling water; condeiising the oil vapors at substantially this same pressure and at a temperatui'e not more.

than 100O F. below the temperature of the vapors produced; and compressing the steam to a pressure at which it can be condensed by said coolingl water.

- 7. A method of producing lubricating oils from petroleum which comprises: distilling Lio a charging stock in the presence of .steam at an absolute pressure lower than the vapor pressure of the available coolinglwater con-V densing,` the oil vaporsat substantially this same pressure and at a temperaature not more than 500 F. below the temperature of 'the vapors produced; and compressingthe steam to a pressure at which it can be condensed by said cooling` water.

8. i method of producing. lubricating` oils from petroleum which comprises: disti'lling` a charging stoel; in the presence otsteain at an a solute pressure lover tl an the vapor pressure of the available cooling water; condensing the oil vr iors at substantially this same 'pressure andl at a temperature not more than Q00 l?. beloaY the temperature of the vapors produced; and compressingl the steam to a pressure.. atwhich it can be con dcuscd by cooling water.

S). [i method of producingl petroleum lubricuting oils substantially free from cracked produls; which comprises: distilling,` said oleum with unavoidable production of red vapors; condensing` the lubricating oil vapors in the presence of suiiicient steam to prevent the condensation of said cracked vapors and at an absolute pressure sufficiently low to prevent the condensation of said steam; and thereafter condensing,` said steam at a higher pressure which is substantially below' atmospheric pressure.

1l). A method ofproducing petroleum lubricating oils substantially free from cracked products, which comprises: distilling said petroleui'n with unavoidable production of cracked vapors; condensing' the lubricating' oil vapors in the presence of sufficient steam toY prevent the condensation of said cracked vapors and at an absolute pressure sufficiently low to prevent the condensation of said steam; and thereafter condensing said steam and cracked vapors at a higher pressure which is substantially below atmospheric pressure. f

11. A method of distilling lubricating oils from petroleum which comprises: remov-v inir lubricating oil by condensation from a space containing lubricating oil `vapors and steam at high temperature land low absolute pressure; and transferring the uncondensed Asteam into a space of lower temperature and higher absolute pressure in which said steam is condensed.

12. A method of producing from petro leum lubricating oils substantially free from undesirable components, which comprises: removing lubricating oil by condensation from a space containing lubricating oil vapors, the vapors of an undesirableV componenti and steam, said condensation takingv place at a suficiently high temperature and low pressure to prevent substantial condensation of said steam and vapors of said un-v desirable component; and transferring said stantial amounts of cracked products; re-

ducing the temperature ofthe resulting mixture of steam` and oil vapors, 'without substantial change in said absolute pressure, to a sufficient degree to condense therefrom the vfdesired lubricating oil fraction; and removing the uncondensed portion of the mixture to a space of higher absolute pressure wherein the steam is condensed.

14E. A method as in claim 13 in which the pressure on the mixed vapors prior to and during the condensation of lubrieatingoil therefrom .is suiiiciently low to prevent the condensation of steam at available cooling water temperatures.

15. A method as in claim 13 in which the pressure on the steam during condensation thereof is sutliciently high to permit condensation of said steam at available cooling water temperatures.

16. A method as in claim 13, in which the temperature at which said lubricating;r oil is condensed is not low enough at the pressure used. during said condensation to cause appreciable condensation of undesirable products.

k17. A process of treating' mineral oils, which comprises: producinga mixture of vapors from a suitable charging stoclrunder a low absolute pressure; cooling,` said mix'- ture of vapors to a sufiicient degree to condense therefrom a certain portion thereof; increasing the absolute pressure on the remaining vapors to a value which is still considerably less than atmospheric pressure; and subjecting said remaining vapors to a further condensation.

18. A process of treating mineral 'oils to produce therefrom certain products, which comprises: producing` a mixture of oil vapers and steam at a low absolute pressure; cooling' said mixture to such a degree that a desired oil fraction condenses therefrom without substantial condensation of water vapor; Aincreasing;- the absolute pressure on the uncondensed vapors to a degree which is still below atmospheric pressure; and subjecting; said vapors at said higher pressure to a further condensing action.

19. A process of treating" mineral oils to produce therefrom certain products7 which comprises: producing' a mixture of oil vapor and steam at a low absolute pressure; cooling said mixture to such a degree that l (ll) a desired oil fraction `condenses therefrom without substantial condensation of water vapor and without substantial increase in said absolute pressure; increasing the absolute pressure yon the uncondensed vapors to a degree which is still below atmospheric pressure; and subjecting said vapors at said higher pressure to a further condensing action.

20. A process of producing v a lubricating oil from a suitable charging stock, which comprises: heating the charging stock to produce a complex mixture of vapors therefrom under low absolute pressureycooling said Acomplex mixture of vapors under substantially the same pressure tosuch a degree thatthe desired lubricating oil fraction condenses therefrom; increasing` the pressure on the uncondensed vapors to a value still con- `and subjecting said uncondensed vapors at said higher pressure to further condensation;

2l. A process of produc-ing lubricating oils, which comprises: heating a suitable charging .stock in the presence of Water vapor land at a low absolute pressure to pro* duce a mixture oi vapors; cooling said vapors to a sufficient degree to condense therefrom a desired lubricating fraction; increasing the pressure on the uncondensed vapors to a value which is below atmospheric; and subjecting' said vapors at said higher pressure to a further condensation.

In testimony whereof, I have Vhereunto set my hand at ll/llartinez7 California, this 1st day of May, 1925. j

GUSTAV A. KRAMER. 

